Canadian Anaphylaxis Network- Predicting Recurrence After Emergency Presentation for Allergic REaction

BACKGROUND: Anaphylaxis is the most severe form of allergy that rapidly affects multiple body systems and can be deadly. The highest incidence of anaphylaxis is in children and adolescents. In Canada, approximately every 10 minutes there is an Emergency Department (ED) visit for food allergy, and up to 80% of anaphylactic reactions in children are triggered by food. The ambiguity in how physicians manage anaphylaxis adds a huge burden to health care and further contributes to ED crowding. Current Canadian and international treatment guidelines universally recommend that all patients present to the ED for a prolonged period (6-24 hours) of in-hospital monitoring after initial reactions have been treated, to increase detection of biphasic anaphylaxis (BA). BA is a second wave of symptoms after initial resolution. These guidelines are based on poor or little evidence and have unintended negative impacts on patient safety and quality of life. Furthermore, this 'one-size fits all' approach to care leads to wasteful resource utilization that provides low value care. OBJECTIVE: The main objective of the study is to derive a clinical prediction rule that identifies children with anaphylaxis who are at risk of BA. METHODS: This prospective multicenter cohort study will enroll 1682 patients from 7 pediatric EDs that are members of the Pediatric Emergency Research Canada (PERC) network. We will enroll patients \< 18 years of age presenting to the ED with an allergic reaction that matches the diagnostic criteria of anaphylaxis. Research assistants (RA) present in the ED will screen, obtain consent, and prospectively collect all study data. The Research Assistant or Research Nurse will follow patients during their ED visit and ascertain, in conjunction with the medical team, if the patient developed biphasic anaphylaxis in the ED. A standardized follow-up survey conducted within 2-5 days of ED or hospital discharge will determine if a biphasic reaction occurred following ED di